Germs are on everything we touch, eat, and breathe in, and on every inch of skin, and despite the advances of science, germs are challenging medicine in ways that were unimaginable a decade ago. The director of clinical microbiology and immunology at NYU's Medical Center, Philip Tierno helped solve the mystery behind toxic shock syndrome. Here he cuts through scientific hoopla and germ paranoia to explain what the greatest threats may be—and what we can do about them. From the common cold, E. coli, and Lyme disease to encephalitis, mad cow disease, and flesh-eating bacteria, Tierno's historical survey of the microscopic world describes how the recycling of matter is the key to life. Along with telling why it's a good idea to clean children's toys, why those fluffy towels may not be so clean, and why you never want to buy a second-hand mattress, he also reveals that there is a lot we can do to prevent germ-induced suffering.